Concrete-working machine with walking vibrators

ABSTRACT

Concrete-working machine component with concrete-spreading auger, vertically adjustable strike-off plate, forwardly projecting, vertically oscillatable arms bearing depending vibrators which reciprocate into and out of the concrete, and crank or cam drives for said arms.

United States Patent Dale 1 Aug. 21, 1973 CONCRETE-WORKING MACHINE WITH 1,953,825 4/1934 Finley 94/49 WALKING VIBRATORS 3,377,933 4/1968 Dale 94/45 R 2,903,948 9/1959 Simmonds 94/49 1 Inventor: Charles Harry Dale, Rock Island, 2,098,895 11/1937 Velten 94/49 111. 2,248,103 7 1941 Mall 94/48 [73] Assignee: East Moline Metal Products Company East Moline, [IL Primary Examiner-Nile C. Byers, Jr.

Attorney-Johnston, Root, OKeefi'e, Keil, Thompson [22] Filed: Apr. 16, 1971 & Shurtleff 21 Appl. No.: 134,694

[57] ABSTRACT 52 US. (:1. 404/116 Concrete-Working machine component with concrete- 51 1m. (:1. E0lc 19/38 Spreading auger, vertically adjustable strike-off plate, [58] Field of Search 425/120, 424, 456; forwardly p j g vertically Oscillatable arms bear- 94/45 4 4 ing depending vibrators which reciprocate into and out of the concrete, and crank or cam drives for said arms [56] References Cited 14 Claims, 6 Drawing Figures UNITED STATES PATENTS 2,962,785 12/1960 Young 94/46 R 3,247,770 4/1966 Perkins 94/48 X Patented Aug. 21, 1973 3,753,621

2 Sheets-Sheet l INVENTOR CHARLES HARRY DALE Q m ,n -0 [MW/1P I,

ATTORNEY Patented Aug. 21, 1973 2 Sheets-Sheet f3 IN V E NTOR CHAR LES HARRY DALE AT TO R N EYS CONCRETE-WORKING MAC WITH WALKING VIBRATORS INTRODUCTION The concrete-working machine component of the present invention is particularly adapted for use with machines for spreading, vibrating and finishing of prestressed concrete slabs in elongated T-molds or double T-molds. The molded concrete products are substantially rectangular slabs having one or two longitudinal ribs projecting from a face thereof. The ribs contain a plurality of cables under tension, which are laid in the rib-forming cavities of the bottom wall of the single T-or double T-mold under tension prior to the pouring of concrete into the mold. The slab portion of the concrete may contain wire mesh, reinforcing rods or other concrete reinforcing means.

One of the problems encountered heretofore in the use of concrete spreading, compacting and finishing machines used on single T- or double T-molding forms lies in the area of attainment of suitable vibration of the poured concrete in the longitudinal, rib-forming cavities of such molds. One technique used to attain such vibration is having one or two men stand on the machine who manually dip into and out of the poured concrete, concrete vibrators as the machine moves longitudinally along the form.

The subject invention concerns a concrete-working machine component adapted to be used in association with a rear machine component for compacting or working, e.g., through tamping, and finishing the slab forming portion of the concrete in such single T- or double T-molds. The machine component has at least one and preferably a plurality of motor driven concrete vibrators which dip into and out of the concrete to a depth sufficient to vibrate the poured concrete in the rib-forming longitudinal cavities in the bottom wall of the single T- or double T-mold. These vibrators attain their reciprocal motion into and out of the concrete by the mounting thereof on the forward portion of one or more arms which are vertically oscillatably driven through a power drive. The power drive mechanism preferably embodies a crank or cam for each arm to impart the oscillating motion.

Concrete paving machines known heretofore have utilized vibrators adapted to dip into and out of concrete as a machine goes forwardly along the surface to be paved. For example, Mall U.S. Pat. No. 2,248,103 illustrates ganged, manually operated rocker arms respectively having a vibrator pivotally hung from the forwardly projecting portion of the arm. Mall U.S. Pat. No. 2,223,734 shows a similar type of paving machine with the vibrators being gang-mounted on a manually oscillatable frame. Other U.S. Pats. disclosing vibrators or vibrating compacters adapted to reciprocate or to be moved relative to the poured concrete include U.S. Pat. Nos. 2,255,344, 2,261,659, 2,292,733, 2,332,687, 2,651,979, 3,123,872 and 3,224,064.

THE INVENTION HEREIN Briefly, the subject invention relates to concreteworking machines particularly adapted to impart vibrations to poured concrete at longitudinally spaced intervals as the machine goes forwardly along a concrete form. The machine component with which the subject invention is principally concerned embodies frame means, at least one arm projecting forwardly of the frame means, and means pivotally supporting the arm on the frame means. Power driven means are operatively associated with each forwardly projecting arm to provide substantially vertical, oscillating movement to the forward portion of the arm. This oscillating movement provides vertical movement into and out of concrete poured ahead of the machine by one or more vibrators depending from the forward portion of the respective arms. Preferably, the vibrators are dipped into the mold cavities at 3-6 inch intervals.

The machine component of the subject invention preferably also embodies a rotatable auger extending transversely of the frame means behind the vibrator(s). This auger preferably is rotatably driven by drive means (not shown) permitting it to be rotated in either direction to attain satisfactory spreading of the concrete between the side walls of the form. A vertical, strike-off plate positioned contiguous to and behind the auger extends transversely of the frame means. its lower edge strikes off poured concrete accumulated against the front face of the strike-off plate and provides a substantially flat upper surface to the poured concrete in the mold. In the machine component of the subject invention, the strike-off plate is mounted on the frame means in vertically adjustable relation to the frame means to provide the desired depth of strike off by said lower edge.

The preferred embodiment of the invention has, for each rib-forming cavity of the T-mold, at least two arms contiguous to each other, each arm being oscillatably driven by the power drive means, preferably about out of phase. The vibrators on the respective arms are substantially aligned one behind the other. With the aforesaid 180 out of phase drive, one vibrator is dipping into the poured concrete in the mold while the other is being withdrawn.

The pivotal support of respective arms preferably is attained through substantially vertical, oscillatable arm means pivotally supported on the frame means and pivotally connected to the rearward portion of each respective arm. The oscillatable arm means permit each forwardly projecting arm and the respective vibrator depending therefrom to move in substantial reciprocating action within predetermined limits, the advantages of which are hereinafter described.

The power drive means for the respective arms preferably embody a crank or cam for imparting the vertical oscillating motion to the forward portion of each arm. With a crank drive, the rod connecting the crank arm to the forwardly projecting arm preferably is rigidly connected to the forwardly projecting arm. Such rigid connection imparts to the substantially vertical oscillatable arm means a positive oscillating motion determined by the orbital movement of the crank arm. The crank itself preferably is oriented in terms of its direction of orbit so that it orbits through the lower half of its rotation cycle in a rearward direction. This relationship imparts a rearward movement to the forwardly projecting arms and vibrators depending therefrom in a direction opposite to the direction of forward movement of the machine while the vibrators are dipped into the poured concrete. Such rearward movement in part or in whole, depending upon the velocity of forward movement of the machine and rate of rotation of the crank, cancels out the effect of forward movement of the machine while the vibrators are dipped into the concrete, whereby the vibrators remain in substantially vertical position while they are in the concrete and are not pivoted rearwardly as a result of said forward motion to any significant extent.

In another preferred form of the invention, the power driven means for the forwardly projecting arms include a rotatable cam with the cam follower for the cam mounted on the forwardly projecting arm. In this embodiment, the substantially vertical, oscillatable arm I means has associated therewith and coacting therewith stop means to limit pivotal movement of the arm means. The follower preferably is mounted on its respective arm by mounting means providing a plurality of positions for mounting the follower at longitudinally spaced intervals along the arm. Such plurality of positions permits the follower to be laid closer to or further away from the pivotal support of the rearward portion of the forwardly projecting arm and thereby adjust the range of vertical movement of the forward portion of such arm and the vibrator depending therefrom. Where the pivotal support for the rear portion of the forwardly projecting arm is the aforesaid substantially vertical, oscillatable arm means, the base of the latter is mounted on the frame means in any one of a plurality of positions spaced in similar, longitudinal intervals to the longitudinally spaced intervals for mounting the cam follower on the forwardly projecting arm.

DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are illustrated in the drawings wherein:

FIG. 1 is a perspective view of a first embodiment of the aforesaid concrete-working machine component and its relationship to a double T concrete mold, shown in fragment;

FIG. 2 is a side elevation illustrating the crank drive and vertical arm pivotal support for the forwardly projecting, vibrator supporting, vertically oscillatable arms;

FIG. 3 is a fragmentary, exploded view of the vertically adjustable means for mounting the strike-off plate on the frame means of the machine component;

FIG. 4 is a side elevation, partly in cross section, similar to FIG. 2 wherein the forwardly projecting arm is vertically oscillated by a cam drive;

FIG. 5 isa side elevation of an alternate form of cam useful in the embodiment in FIG. 4; and

FIG. 6 is a diagrammatic view of the relative motion imparted to the forwardly projecting arms and the vibrators depending therefrom at 90 intervals in the rotation of the crank drive in the embodiment of FIGS. 1 and 2.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring to the drawings, the concrete-working machine component 10 constitutes the front section of an overall concrete-working machine. The rear section is not illustrated inasmuch as it corresponds substantially to the rear section disclosed in my U.S. Pat. No. 3,377,933, which is incorporated herein by reference. The rear section is used for propelling the machine component 10 forwardly along the concrete mold, e.g., by the cable and winch drive illustrated and described in my aforesaid patent.

The metal frame means 11 for the machine component 10 is composed of side channels 12 and 13; heavy wall, tubular, cross frame members 14 and 15 which are rigidly attached, e.g., by welding, to the inner faces of the side channels 12 and 13 by connector plates 16 and 17; and a platform 18 rigidly attached to and extending across the tops of the tubular frame members 14 and 15.

The front portions of the side channels 12 and 13, respectively, have yokes 26 and 21 in which are rotatably joumalled flanged wheels 22 and 23. These wheels ride on rails 25 and 26, which in turn are fixedly attached to the flanges 27 and 28 of the side walls 29 and 30 of the elongated, concrete mold 31. The bottom wall 32 of the mold contains, in the case of double T molds, a pair of parallel, longitudinally extending, elongated cavities 33, one of which is illustrated and the other of which is disposed directly under the vibrators 60a and 60b. In the case of molding of prestressed concrete slabs with one or two ribs, the cavities 33 have longitudinally disposed therein a plurality of tensioned cables, usually lying in a vertical plane about midway between the side walls of the cavities 33. Wire mesh or other reinforcing means may be laid in the mold over the bottom wall 32 to reinforce the slab-forming portion of the molded concrete product.

Theconcrete-working machine component 10 has at the rear portions of the side channels 12 and 13 upper coupling members 35 and lower coupling members 36 by which the machine component 10 is coupled to the aforesaid rear section described in my aforesaid patent. Referring to said patent, the rear section in the overall machine herein contemplated preferably embodies at least a cable and winch forward propulsion mechanism and power drive therefor; the tamper bar and its drive mechanism, the power units and control unit, a flat or crowned pan beneath the frame of the rear section, which pan need not embody the crown adjustable mechanism nor the curb forming sheet which is illustrated and described in my aforesaid patent, and optionally the reciprocable, rear finishing screed.

The front machine component 10 of the subject invention has an auger 40 extending across the machine between the side channels 11 and 12, which auger is rotatably joumalled on the side channels and is rotatably driven and controlled from the rear section of the machine is described and illustrated for the auger in my aforesaid patent. A vertically adjustable strike-off plate 41 extends between the side channels 12 and 13 immediately behind the auger. The reversibledrive for the auger is used by the machine operator to maintain an accumulation of wet concrete across the entire length of the strike-off plate 41, the lower edge 42 of which (FIG. 3) strikes off and levels the upper surface of the wet concrete. The rear section of the machine may also embody a strike-off plate set at the same or a slightly lower level than the strike-off plate'4l. See, for example, the strike-ofi' plate in my aforesaid patent.

The strike-off plate 41 is mounted on the frame means 11 in vertical, adjustable relationship thereto by a pair of hydraulically operated, vertical adjustment means 43 and 44. The components of the vertical adjustment means 43 and 44 are illustrated in FIG. 3. The front, tubular cross frame member 15 and/or respective mounting plates 16 and 17 have fixedly secured thereto, e.g., by welding, a metal L-channel 46. A U- frame 47 is rigidly attached to the front face of the L- channel 46. A wider, inverted U-frame 48 fits telescopically over the U-frarne 47 as illustrated in FIG. 1. A hydraulic cylinder 49 with a piston rod 50 is positioned inside the frames 47 and 48. A yoke 51 on the end of the piston rod 50 is coupled by a bolt or pin (not illustrated) to the cross legs 52 of the inverted U-frame 48 with the bolt or pin extending through apertures 53 in the cross legs and apertures in the yoke 51. The inverted U-frame 48 is rigidly attached to the rear face of the strike-off plate 41.

The yoke 54 of the hydraulic cylinder is coupled in a similar manner by bolts or pins (not illustrated) extending through apertures 56 in the cross legs of the U- frame 47. The respective hydraulic cylinders 49 of the strike-off plates vertical adjustment means 43 and 44 are coupled by conventional hydraulic fluid lines to the hydraulic control and pressure system provided on the rear section of the machine.

The machine as illustrated has four concrete vibrators 60a, 60b, 60c and 60d which dip into and out of the wet concrete poured in the concrete mold ahead of the machine. These vibrators have an essentially vertical reciprocating motion to a height sufficient to lift them completely out of the wet concrete and to a depth sufficient that the respective lower ends of the vibrators penetrate into the rib-forming cavities 33 in the botto wall 32 of the mold.

Each vibrator 60a, 60b, 60c and 60d is of conventional construction and is driven by respective electric motors 61a, 61b, 61c and 61d. The upper portions of the vibrators are respectively pivotally hung in yokes 62a, 62b, 62c and 62d by pins 63 which allow the vibrators to pivot in a front to rear and rear to front pivotal motion. The yokes 62a, 62b, 62c and 62d and the vibrators hung therein have an oscillating motion in respective vertical planes imparted thereto by the drive imparted to the rear portions of the respective forwardly projecting arms 64a, 64b, 64c and 64d.

The illustrated cam or crank drives for the forwardly projecting arms 64a-d impart a substantially vertical, oscillating movement to the vibrator-supporting, forward portion of each arm. The respective vibrators 6011-11 appear, when the machine is in motion, to have a walking-like action as they dip into and rise out of the wet concrete poured in the mold.

With the preferred vibrator arrangement illustrated in F IG. 1, there are two pairs of contiguous arms 64a, 64b and 64c, 64d, in this case in side-by-side relationship. Thus, two vibrators are dipping into and out of the concrete for each of the mold cavities 33 with the vibrator pairs 60a, 60b and 60c, 60d being substantially aligned one behind the other. The pivotal support 63 of the vibrators in the respective yokes 62a-62d allow them to pivot enough to pass wire mesh and/or cables embedded in the poured concrete in the event that the latter should be struck by the vibrator.

The preferred means for pivotally supporting the respective arms 64a-d is illustrated in FIGS. 1, 2 and 4. This means comprises a pair of substantially vertical, oscillatable arms 66 pivotally connected by hinge structure 67 to a base plate 68. The latter is connected by bolts 69 to the platform 18.

The upper ends of the arms 66 are pivotally connected by hinge structures 70 to a base plate 71 in turn bolted to the lower side of the respective arm 64a-d. In FIGS. 2 and 4, the arm 64a was selected for illustrative purposes.

In the embodiment of FIGS. 1 and 2, the power driven means which provides the substantially vertical, oscillating movement to the forward portion of the respective arm 64a-d is a crank drive 72a, 72b, 72c or 72d. The crank structure in each case embodies a rotatably driven disc 73 having an orbiting crank pin or arm 74 projecting from a face of the disc 73. A bearingcontaining head 75 is rotatably joumalled on the pin or arm 74. The head 75 is bolted to the upwardly extending connector rod 76 at the lower end of the latter. The upper end of the connector rod 76 is rigidly connected by a mounting plate 77 and bolts 78 to the lower side of the arm 64. If desired, spacer plates 79 may be interposed between the arm 644 and the mounting plate 77 to vary the vertically reciprocable path imparted to the respective vibrators Mia-d. Similarly, if desired, spacer plates 79 may be interposed between the base plate 71 and the arm 64a for the same purpose.

The rigid connection between the arm 64a and the connector rod 76 provides a positive oscillating motion to the respective arm means 65a-65d. As the crank pin or arm 74 orbits through the upper half of its rotation circle, the arm means 65a-d are thrust forwardly relative to the machine frame. As the crank pin orbits through the lower half of its circle, the arm means 65a-d are thrust rearwardly, again relative to the frame of the machine.

The aforesaid relative motion is illustrated diagrammatically in P16. 6 wherein the arrows 80 designate the forward motion of the machine along the mold. The arrows 81 designate the relative forward movement of the arm 64a and the vibrator 60a depending therefrom attained through positive oscillation of the arm means 65a. The arrows 82 designate the relative rearward motion imparted to the arm 64a and its vibrator 60a. The latter relative motion occurs when the vibrator has approximately or actually penetrated the upper surface 83 of the poured wet concrete. Thus, while the respective vibrator is in the concrete mass, the relative rearward motion designated by arrows 82 in part or in total, depending upon the linear velocity of the machine and the rate of rotation of the cranks, offsets the forward direction of travel of the machine designated by the arrows 80. This offsetting relationship is advantageous in that the pivotally hung vibrators remain in substantially vertical position while their lower, vibration-imparting ends are in the concrete.

If desired, the crank disc 73 may have one or more alternate crank pins 84 projecting from the face thereof at a different radius than the axis of rotation of the disc 73. These alternate crank pin(s) provide means for changing the amount of oscillating movement of the arm means 65a-d andalso the oscillating movement of the forwardly projecting arms 64ad and thus can be used to vary the intervals at which the respective vibrators 60a-d dip into and out of the concrete as well as the amount of vertical movement of the respective vi brators.

The cranks 72ad are power driven by drive shafts 85 and 86 rotatably joumalled in bearings 91, in turn mounted on the platform 18. The drive shaft 85 is driven by a chain and sprocket coupling 87, one sprocket of which is driven through reduction gear box 88 by a variable speed belt-pulley drive driven by an electric motor 89. Electric cable connections for the motor (not illustrated) are coupled to an electric power source, e.g., the generator and the motor control unit shown on the rear section of the machine described and illustrated in my U.S. Pat. No. 3,377,933. The shaft 86 is driven off the shaft at a 1:1 drive ratio by th chain and sprocket coupling 90.

In the embodiment of FIG. 4, a cam drive is used in lieu of the crank drive for each arm 64a-d, the arm 64a again being used for illustrative purposes. Where applicable, like numerals designate like parts previously described. The cam drive does not provide the rigid connection with the arm 64a which is provided by the illustrated crank drive. Hence, the base plate 68 is mounted on a mounting plate 95 by the bolt 69 in any pair of a plurality of front to rear, aligned, tapped holes 96 in the plate 95, the purpose for which will be later described.

Additionally the base plate 68 has rigidly mounted on its front and rear edges the vertical plates 97 and 98 in which are threadably mounted respective horizontal bolts 99 and W6. These bolts are aligned with the arm 66 and serve as stops which limit the oscillating motion of the arm 66.

The cam 101 and its cam follower 102 impart oscillating movement to the arm 64a and also impart a forward oscillating movement to the arm 66. When the follower R02 is riding on the circular curved portion 107, the vibrators are in the down, concrete penetrating position. As the cam rotates in the arrow direction, its lift-imparting curve 108 oscillates arm 64a upwardly while at the same time imparting a forward thrust against the cam follower 102. This thrust causes the arms 66 to oscillate forwardly until they contact the bolts 100. The relatively straight cam surface: 109 allows the vibrators to drop relatively rapidly into the wet poured concrete while at the same time permitting the arm 66 to be oscillated rearwardly as a result of forward motion of the machine relative to the concrete in which the lower end of the vibrator is buried. The arms 66 are thus oscillated rearwardly by thrusts imparted through the vibrator and its arm until the arms 66 strike bolts 99.

The cam 101 of FIG. 4 has an indentation 105 which extends the circular curve 107 and thus keeps the respective vibrator in the lower position for a longer period of time.

if desired, however, the cam may be made without the indentation 105 in accordance with the shape of the cam E06 shown in FIG. 5 wherein the circular curve 107 and the lift-imparting curve 108 merge smoothly into each other.

The amount of oscillating movement imparted to the arm 64a by the cam drive can be changed by moving the oscillatable arms 66 closer to or further away from the cam 101 or 106 by changing the position of the.

bolts 69 into another pair of tapped holes 96 in the mounting plate 95. The cam follower 102 is shifted a corresponding amount by the mounting thereof between a pair of plates 103, each containing a horizontal row of apertures 104 spaced at intervals corresponding substantially to the spacing of tapped holes 96. By way of illustration, the cam follower 102 may be a cylinder rotatably journalled on a removable bolt or pin in turn supported in one of the apertures 104 of each of the plates 103.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, pivot means pivotally supporting said arm on said frame means for substantially vertical, oscillating movement of said arm, power driven means connected to said arm at a point on said arm forwardly of said pivot means and providing said oscillating movement by the forward portion of said arm, said power driven means including means to change the amount of vertical oscillation of the forward ends of said arm, an elongated power-driven vibrator having its upper portion mounted on the forward portion of said arm and depending vertically therefrom, the lower end of said vibrator adapted to be moved up and down into and out of poured concrete by the oscillating move ment of said forward portion of said arm.

2. A machine as claimed in claim 1, said machine having at least two of said arms contiguous to each other, and the respective elongated vibrators depending vertically therefrom being substantially aligned one behind the other.

3. A machine as claimed in claim 1, wherein said pivot means comprises substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm.

4. A machine as claimed in claim 3, said power driven means including a crank having a crank rod connected to said arm forwardly of said oscillatable arm means.

5. A machine as claimed in claim 4, and means rigidly attaching said crank rod to said arm whereby rotation of said crank imparts via its crank rod positive oscillating motion to said oscillatable arm means.

6. A machine as claimed in claim 5 wherein the crank arm of said crank orbits in the lower half of its rotation cycle in a rearward direction.

7. A machine as claimed in claim 3, said power driven means including a rotatable cam, and a cam fol lower for said cam mounted on said arm.

8. A machine as claimed in claim 1, and a rotatable auger extending transversely of said frame means behind said vibrator.

9. A machine as claimed in claim 8, a vertical strikeoff plate extending transversely of said frame means and positioned behind said auger, and means mounting said plate on said frame means in vertically adjustable relation of said plate to said frame means.

10. A machine as claimed in claim 1, said vibrator having its upper portion pivotally supported on the forward portion of said arm by pivot means allowing forward and rearward pivotal movement of said vibrator.

11. A machine as claimed in claim 10, said vibrator comprising an elongated vibrator member driven by a motor on the upper end thereof.

12. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, means pivotally supporting said arm on said frame means, power driven means providing substantially vertical, oscillating movement by the forward portion of said arm, a power-driven vibrator depending from the forward portion of said arm and adapted to be moved up and down in poured concrete by the oscillating movement of said forward portion of said arm, said first-mentioned means comprising substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm, said power driven means including a rotatable cam and a cam follower for said cam mounted on said arm, and stop means coacting with said oscillatable arm means to limit pivotal movement of said arm means.

13. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, means pivotally supporting said am on said frame means, power driven means providing substantially vertical, oscillating movement by the forward portion of said arm, a power-driven vibrator depending from the forward portion of said arm and adapted to be moved up and down in poured concrete by the oscillating movement of said forward portion of said arm, said first-mentioned means comprising substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm, said power driven means including a rotatable cam and a cam follower for said cam mounted on said arm, and means mounting said follower on said arm and providing a plurality of positions for mounting said follower at longitudinally spaced intervals along said arm.

14. A machine as claimed in claim 13, and means for mounting said oscillatable arm means on said frame means in a plurality of positions spaced in similar longitudinal intervals to said longitudinally spaced intervals along said arm.

* l l 0! l 

1. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, pivot means pivotally supporting said arm on said frame means for substantially vertical, oscillating movement of said arm, power driven means connected to said arm at a point on said arm forwardly of said pivot means and providing said oscillating movement by the forward portion of said arm, said power driven means including means to change the amount of vertical oscillation of the forward ends of said arm, an elongated power-driven vibrator having its upper portion mounted on the forward portion of said arm and depending vertically therefrom, the lower end of said vibrator adapted to be moved up and down into and out of poured concrete by the oscillating movement of said forward portion of said arm.
 2. A machine as claimed in claim 1, said machine having at least two of said arms contiguous to each other, and the respective elongated vibrators depending vertically therefrom being substantially aligned one behind the other.
 3. A machine as claimed in claim 1, wherein said pivot means comprises substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm.
 4. A machine as claimed in claim 3, said power driven means including a crank having a crank rod connected to said arm forwardly of said oscillatable arm means.
 5. A machine as claimed in claim 4, and means rigidly attaching said crank rod to said arm whereby rotation of said crank imparts via its crank rod positive oscillating motion to said oscillatable arm means.
 6. A machine as claimed in claim 5 wherein the crank arm of said crank orbits in the lower half of its rotation cycle in a rearward direction.
 7. A machine as claimed in claim 3, said power driven means including a rotatable cam, and a cam follower for said cam mounted on said arm.
 8. A machine as claimed in claim 1, and a rotatable auger extending transversely of said frame means behind said vibrator.
 9. A machine as claimed in claim 8, a vertical strike-off plate extending transversely of said frame means and positioned behind said auger, and means mounting said plate on said frame means in vertically adjustable relation of said plate to said frame means.
 10. A machine as claimed in claim 1, said vibrator having its upper portion pivotally supported on the forward portion of said arm by pivot means allowing forward and rearward pivotal movement of said vibrator.
 11. A mAchine as claimed in claim 10, said vibrator comprising an elongated vibrator member driven by a motor on the upper end thereof.
 12. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, means pivotally supporting said arm on said frame means, power driven means providing substantially vertical, oscillating movement by the forward portion of said arm, a power-driven vibrator depending from the forward portion of said arm and adapted to be moved up and down in poured concrete by the oscillating movement of said forward portion of said arm, said first-mentioned means comprising substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm, said power driven means including a rotatable cam and a cam follower for said cam mounted on said arm, and stop means coacting with said oscillatable arm means to limit pivotal movement of said arm means.
 13. A machine adapted for imparting vibrations to poured concrete at spaced intervals comprising frame means, at least one arm projecting forwardly of said frame means, means pivotally supporting said arm on said frame means, power driven means providing substantially vertical, oscillating movement by the forward portion of said arm, a power-driven vibrator depending from the forward portion of said arm and adapted to be moved up and down in poured concrete by the oscillating movement of said forward portion of said arm, said first-mentioned means comprising substantially vertical, oscillatable arm means pivotally supported on said frame means and pivotally connected to said arm, said power driven means including a rotatable cam and a cam follower for said cam mounted on said arm, and means mounting said follower on said arm and providing a plurality of positions for mounting said follower at longitudinally spaced intervals along said arm.
 14. A machine as claimed in claim 13, and means for mounting said oscillatable arm means on said frame means in a plurality of positions spaced in similar longitudinal intervals to said longitudinally spaced intervals along said arm. 